Needle-free injection systems provide an alternative to standard fluid delivery systems, which generally use a needle adapted to penetrate the outer surface of a target. Typically, needle-free injection systems are designed to eject the fluid from a fluid chamber with sufficient pressure to allow the fluid to penetrate the target to the desired degree. For example, common applications for needle-free injection systems include delivering intradermal, subcutaneous and intramuscular injections into or through a recipient's skin. For each of these applications, the fluid must be ejected from the system with sufficient pressure to allow the fluid to penetrate the tough exterior dermal layers of the recipient's skin.
Examples of needle-free injection systems and components are found in U.S. Pat. Nos. 4,592,742, 4,596,556, 4,790,824, 4,940,460, 4,941,880, 5,062,830, 5,064,413, 5,312,335, 5,312,577, 5,383,851, 5,399,163, 5,503,627, 5,505,697, 5,520,639, 5,746,714, 5,782,802, 5,893,397, 5,993,412, 6,096,002, 6,132,395, 6,216,493, 6,264,629, 6,319,224, 6,383,168, 6,415,631, 6,471,669, 6,506,177, 6,572,581, 6,585,685, 6,607,510, 6,641,554, 6,645,170, 6,648,850, 6,623,446, 6,676,630, 6,689,093 6,709,427, 6,716,190, 6,752,780, 6,752,781, 6,783,509, 6,935,384, 6,942,645, 6,979,310, 6,981,961, 7,056,300 and 7,156,823; U.S. Patent Application Publication Nos. 2005/0119608 and 2006/0189927; and International Publication No. WO 00/72908, the disclosures of which are incorporated herein by reference, in their entirety and for all purposes.